Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. Traffic flow information may be used to predict travel times along various prospective or potential vehicle routes. The traffic flow information may be incorporated into a route recommendation algorithm of a Global Positioning System (GPS) based navigation and mapping system to recommend a route for a vehicle to travel. Traffic flow information, for example, can be gathered from various sources such as in-road speed sensors, cameras, and other types of fixed measurement devices or reported from individual vehicles as they travel. The accuracy of predicted travel times may be an important factor for vehicles to determine which route to travel.